Abstract:

An arrangement includes a solar energy receiving device and at least one
component in thermal communication with the solar energy receiving
device, the at least one component formed from a composite material, the
composite material may comprise a matrix of carbon-based fibers, the
carbon-based fibers comprising one or more of: mesophase carbon, carbon
nanotubes, graphite, graphene and pan carbon. According to a further
optional aspect, there is provided a solar energy receiving device
comprising a first surface for receiving solar energy incident thereon,
and a second opposing surface, the second surface being electrically
conductive; at least one heat transport device in direct contact with at
least a portion of the second surface, the at least one heat transport
device may comprise at least one internal passage and at least one duct;
and a heat transport media flowing within the at least one internal
passage and at least one duct. Related methods and additional
arrangements are also described.

Claims:

1. An arrangement comprising:a solar energy receiving device; andat least
one heat transport device in thermal communication with the solar energy
receiving device, the at least one heat transport device formed from a
composite material, the composite material comprising a matrix of
carbon-based fibers, the carbon-based fibers comprising one or more of:
mesophase carbon, carbon nanotubes, graphite, graphene and pan carbon.

2. The arrangement of claim 1, wherein the composite material further
comprises one or more of a filler contained within the fibers, and a
coating disposed thereon,the filler comprising one or more of: carbon
nanotubes, diamond, boron nitride, aluminum nitride and silver, andthe
coating comprising one or more of: aluminum, copper, silver, boron
nitride, aluminum nitride, diamond, and carbon nanotubes.

3. The arrangement of claim 2, wherein the composite material comprises
both the filler and the coating.

4. The arrangement of claim 1, wherein the solar energy receiving device
comprises a concentrator capable of magnifying the intensity of the sun
by at least 1,000 times, and as much as 10,000 times.

5. The arrangement of claim 1, wherein the solar energy receiving device
comprises a solar cell, the solar cell comprising a first planar surface
for receiving solar energy incident thereon, and a second opposing planar
surface, the second surface being electrically conductive, wherein the at
least one heat transport device is in direct contact with at least a
portion of the second surface.

13. The arrangement of claim 1, wherein the at least one heat transport
device has a density of at least 80%.

14. The arrangement of claim 1, wherein the at least one heat transport
device has a density of at least 89%.

15. The arrangement of claim 1, wherein the fibers have a diameter of
approximately 2 nm-100 μm.

16. The arrangement of claim 1, wherein the at least one heat transport
device comprises a plurality of layers.

17. The arrangement of claim 1, wherein the at least one heat transport
device comprises at least one internal passage and at least one duct.

18. The arrangement of claim 5, wherein the at least one heat transport
device comprises an internal passage and at least one duct, the at least
one heat transport device is in direct contact with the second surface.

19. A heat transport device comprising:an internal passage;at least a
portion of the internal passage formed from a composite material, the
composite material comprising a matrix of carbon-based fibers, the
carbon-based fibers comprising one or more of: mesophase carbon, carbon
nanotubes, graphite, graphene and pan carbon.

20. The device of claim 19, further comprising at least one duct disposed
in the passage; and the at least one duct formed at least in part from
the composite material.

21. The device of claim 19, wherein the composite material further
comprises one or more of a filler contained within the fibers and a
coating disposed thereon;the filler comprising one or more of: carbon
nanotubes, diamond, boron nitride, aluminum nitride and silver, andthe
coating comprising one or more of: aluminum, copper, silver, boron
nitride, aluminum nitride, diamond, and carbon nanotubes.

22. The device of claim 21, wherein the composite material comprises both
the filler and the coating.

23. The device of claim 19, wherein the composite material has a fiber
density of at least 80%.

24. The device of claim 19, wherein the composite material has a fiber
density of at least 89%.

25. The device of claim 19, wherein at least some of the fibers form a
woven fabric.

26. The device of claim 19, wherein the composite material has an
anisotropic thermal conductivity.

27. The device of claim 19, wherein each of the fibers exhibit a thermal
conductivity in the x, y, and z directions, as represented by Kx, Ky, and
Kz, wherein Kx>Kz and Ky>Kz.

28. The device of claim 19, wherein the at least one duct has a height to
width ratio of at least 10:1.

29. The device of claim 19, wherein the at least one duct comprises at
least one of nanogrooves, nanoprojections and carbon nanotubes disposed
therein to increased turbulent flow within the at least one duct.

30. The device of claim 19, further comprising a heat transfer media
contained in the internal passage.

[0002]The present invention is in the technical field of composite
materials. The present invention is in the technical field of heat
transport, extraction, and cooling. The present invention is also related
to heat transport, extraction, cooling, storage and management for solar
thermal, photovoltaic and other solar electric power generation, as well
as all types of cooling and heat management, including but not limited to
the electronics industry in general.

BACKGROUND

[0003]In this specification where a document, act or item of knowledge is
referred to or discussed, this reference or discussion is not an
admission that the document, act or item of knowledge or any combination
thereof was at the priority date, publicly available, known to the
public, part of common general knowledge, or otherwise constitutes prior
art under the applicable statutory provisions; or is known to be relevant
to an attempt to solve any problem with which this specification is
concerned.

[0004]While there are many different structures, arrangements and
techniques for heat transportation, extraction and cooling in the state
of the art, there is a need for improved structures, arrangements and
techniques for cooling and heat transportation which have improved
efficiency. For example, there is a need for such improvements in the
areas of solar thermal, photovoltaic and other solar electric power
generation, nuclear power generation cooling, as well as in the
electronics industry, in general.

[0005]Cooling of photovoltaic cells is one of the main concerns when
designing concentrating photovoltaic systems. Cells may experience both
short-term (efficiency loss) and long-term (irreversible damage)
degradation due to excess temperatures. Concentrating solar energy
maximizes the ability to derive other forms of output therefrom. However,
very high heat densities are often produced by sun concentrations of more
than 1,000 times the nominal concentration of the sun's energy. This
concentration is sometimes referred to as "1,000×" or "1,000 suns."
Some or all parts of an arrangement that are exposed to these levels of
heat density may be destroyed or are rendered ineffective or inefficient.
Consequently, at least some commercially available solar cells specify
that they are not intended for use above 1,000 suns.

[0006]Design considerations for cooling systems include low and uniform
cell temperatures, system reliability, sufficient capacity for dealing
with worst case scenarios, and minimal power consumption by the system.
For instance, an active cooling system with a thermal resistance of less
than 10-4 K m2/W is typically necessary for solar cells under
high concentrations (>150 suns).

[0007]Conventional nuclear power generation cooling systems typically
require large volumes of water. Thus, it is common to locate nuclear
power plants in close proximity to large bodies of water, such as lakes.
However, severe drought conditions, which may become more prevalent due
to climate change, can diminish the availability of enough water to
provide adequate cooling. This can result in a disruption of the
generation of electrical power. Thus, there is a need to provide a way to
enable adequate cooling of nuclear power generation operations with lower
volumes of cooling media than is currently utilized.

[0009]The invention can be utilized in a number of potential applications,
including but not limited to solar thermal, photovoltaic and other solar
electric power generation applications. The present invention includes
materials, arrangements, systems and methods that may be used in
applications with very high heat densities produced by sun concentrations
of up to, for example, 10,000×.

[0010]Heat management for solar electric power generation involves
efficient extraction and transportation of heat generated by the solar
cell with an incident concentrated solar energy strength of up to, for
example, 10,000×. There are at least two notable aspects of this
system: cooling the solar cells and transporting the heat away for other
utility applications such as hot water and/or steam. Heat management for
solar thermal power generation involves efficient extraction and
transportation the heat absorbed by the heat collector subsystem with an
incident sunlight concentration of up to, for example, 10,000×.
There are at least two notable aspects of this system: collection of heat
and transporting the heat away for other utility applications such as hot
water and/or steam.

[0011]According to one aspect of the present invention there is provided
an arrangement comprising: a solar energy receiving device; and at least
one heat transport device in thermal communication with the solar it
energy receiving device, the least one heat transport device formed from
a composite material, the composite material comprising a matrix of
carbon fibers, the carbon fibers comprising one or more of: mesophase
carbon, carbon nanotubes, graphite, graphene and pan carbon.

[0012]According to a further aspect, the present invention provides a heat
transport device comprising: an internal passage; and at least a portion
of the internal passage formed from a composite material, the composite
material comprising a matrix of carbon fibers, the carbon fibers
comprising one or more of: mesophase carbon, carbon nanotubes, graphite,
graphene and pan carbon.

[0013]According to a further aspect, there is provided a solar energy
receiving device comprising a first surface for receiving solar energy
incident thereon, and a second opposing surface, the second surface being
electrically conductive; at least one heat transport device in direct
contact with at least a portion of the second surface, the at least one
heat transport device comprises at least one internal passage and at
least one duct; and a heat transport media flowing within the at least
one internal passage and at least one duct.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a schematic illustration of the molecular structure of
carbon fiber.

[0015]FIG. 2 is a schematic illustration of thermal gradients present in
an anisotropic fiber.

[0016]FIGS. 3A and 3B are schematic illustrations of plated fibers before
and after sintering.

[0017]FIG. 4 is schematic illustration of a portion of the fiber matrix,
including illustration of heat path and thermal gradient behaviors.

[0018]FIG. 5 is a schematic illustration of a basic building block
construction including multiple layers of a designer composite.

[0019]FIG. 6 is a schematic illustration of a designer composite in the
form of an anisotropic XY cross weave, including the matrix material in
the Z direction.

[0020]FIG. 7 is a schematic illustration of a micro/nano cooling or heat
transport channel arrangement.

[0021]FIG. 8 is a schematic illustration of certain optional details of
the arrangement of FIG. 7.

[0022]FIG. 9 is a schematic cross-sectional illustration of an arrangement
formed according to an additional aspect of the present invention.

[0023]FIG. 10 is a schematic illustration of an end view of the
arrangement of FIG. 9.

[0024]FIG. 11 is a schematic illustration of an arrangement including a
solar cell and a cooling or heat transport arrangement formed according
to one aspect of the present invention.

[0025]FIG. 12 is a schematic illustration of an arrangement including a
solar cell and a cooling or heat transport arrangement formed according
to a further aspect of the present invention.

DEFINITIONS

[0026]Unless otherwise defined herein or below in the remainder of the
specification, all technical and scientific terms used herein have
meanings commonly understood by those of ordinary skill in the art to
which the present invention belongs.

[0027]Before describing the present invention in detail, it is to be
understood that the terminology used in the specification is for the
purpose of describing particular embodiments, and is not necessarily
intended to be limiting. As used in this specification and the appended
claims, the singular forms "a", "an" and "the" do not preclude plural
referents, unless the content clearly dictates otherwise.

[0028]Although many methods, structures and materials similar, modified,
or equivalent to those described herein can be used in the practice of
the present invention without undue experimentation, the preferred
methods, structures and materials are described herein. In describing and
claiming the present invention, the following terminology will be used in
accordance with the definitions set out below.

[0029]As used herein, the term "heat receiving device" or "electromagnetic
energy receiving device" means one or more devices arranged for receiving
one or more forms of electromagnetic energy, such as solar energy,
infrared energy, far infrared energy, microwave energy, sound energy,
phonon energy, or radio waves, and possibly converting the
electromagnetic energy incident thereon to one or more forms of energy
which differ than the form which is incident thereon. The converted
energy may take the form of electrical current, heat, mechanical energy
and/or fluid pressure. Such heat receiving devices include, but are not
limited to, photovoltaic solar cells and passive solar devices. One
example of a comprehended passive solar device is a tube or other
structure for transporting a heated fluid.

[0030]As used herein, the term "heat transfer media" means a vapor, a
single fluid, mixed fluids, or multiphase fluids. The heat transfer media
may have any suitable pressure, including pressures equal to, less than,
or higher than, atmospheric pressure. The heat transfer media may
include, but is not limited to, one or a combination of: organic fluid,
inorganic fluid, biological fluid, water, steam, oil, and particles or
structures of organic, inorganic or biological materials. When present in
the form of a mixture, the heat transfer media may take the form of a
colloidal dispersion or emulsion.

[0031]As used herein, the term "duct" shall mean one or more structures
capable of conducting the heat transfer media therethrough. The duct
includes structures such as channels, canals, tubes, conduits,
passageways, tubules and capillaries. The term "duct" is not limited to
any particular material, cross-sectional geometry or dimension. For
purposes of illustration, the duct can be provided with dimensions on the
order of 1 nm to a few centimeters.

[0032]As used herein, the term "designer" or "designer material" refers to
the ability to control physical and/or thermal properties in the X, Y, Z
material indices. Designer materials have made-to-order properties in one
or more of the three dimensions.

DETAILED DESCRIPTION

[0033]According to certain aspects of the present invention, a variety of
anisotropic materials, composites, thin films and matrices having high
thermal conductivity have been developed. These materials can be used in
any number of different applications. For example, the materials of the
present invention can be used to provide unexpectedly superior results as
heat transport devices such as solar cell package substrate material,
micro-channel heat transport devices and fluidic systems, component
mounts, connectors, thermal interface materials, heat spreaders, heat
sinks, heat pipes, vapor chambers, thermoelectric devices, cooling
components in nuclear power generation operations and other cooling
components.

[0034]The materials of the present invention can be characterized as
designer materials. Generally, conventional composites are made simply by
mixing materials of different physical properties, with no special
ordering within the composite and can only demonstrate bulk properties.
By contrast, the designer materials of the present invention demonstrate
different physical properties, thermal conductivity being a very
important physical property for cooling and heat transport applications,
in different directions and parts of the composite. In addition to
thermal conductivity, one or more of the following properties may be
tailored: coefficient of thermal expansion (CTE); thermal spreading
coefficient Ke; and isothermal morphing of heat flux.

[0035]Designer materials of the present invention are anisotropic
composites and matrices that are thinner, lighter, and stronger, and have
eccentric heat spreading. Eccentricity is an important and major property
in the designer materials. Heat spreading behavior in the X, Y and Z
dimensions can be custom designed based on the application needs. In
addition, the thermal conductivity and heat spreading could be custom
designed to vary even along X, Y and Z axes. For example, the thermal
properties in X direction could change as the value of X changes, which
is along its length. In addition, the thermal conductivity and heat
spreading could be custom designed to vary even along X, Y and Z axes.
For example, the thermal properties in X direction could change as the
value of X changes, which is along its length. If the heat spreading in
an isotropic material could be visualized as a spheroid, the designer
techniques enable making the shape an ellipsoid or even any random shape.
Another way to visualize the power of the designer paradigm is an onion
made up of layers, in which each layer could have different thermal
properties, and different even within the layer surface.

[0036]Generally speaking, the designer materials of the present invention
may comprise an anisotropic carbon-based fiber component and at least one
of a high thermal conductivity filler and a high thermal conductivity
coating or cladding.

[0037]The anisotropic carbon-based fibers can comprise one or more of:
mesophase carbon fiber, carbon nanotube (CNT) based carbon fiber,
graphene-based carbon fiber, graphite-based carbon fiber, and
polyacrylonitrile (PAN) based carbon fiber. The carbon fiber may be
derived from pitches, as well known in the art. Optionally, according to
alternative embodiments, the fibers may be formed from copper, or be clad
with copper.

[0038]According to one embodiment of the present invention, the fiber
component of the composite comprises mesophase carbon fiber. Many
materials containing polymers can be converted at early stages of
carbonization to a structurally ordered anisotropic liquid crystals
called mesophase, which can in turn be used to produce an anisotropic
high quality carbon fiber.

[0039]The molecular structure 10 of one of the carbon materials used in
the composites of the present invention is illustrated in the FIG. 1. The
hexagonal crystalline structure 12 in the XY plane has high covalent
bonding 14 responsible for high thermal conductivity in this plane.
However, the adjacent planes in the Z direction have weak Van der Walls
bonding 16. This combination of high thermal conductivity in the XY
direction, with significantly less conductivity in the Z direction makes
the material anisotropic as indicated by the indication of relevant heat
flow 18.

[0040]As illustrated in FIG. 2, the thermal conductivity of
mesophase-based carbon fibers 20 is anisotropic with very high
conductivity in X-direction or along the length of the fiber, while where
the thermal conductivity along its Z-direction or thickness or diameter
is very poor. This behavior is indicated by the illustrated isotherms 24
and thermal gradient 26. Thermal conductivity of the mesophase-based
carbon fiber along its length ranges from 100 watts per meter-Kelvin
(W/mK) to 5,000 watts per meter Kelvin. The thermal conductivity in the
thickness direction is less than 50 watts per meter-Kelvin.

[0041]The anisotropic carbon-based fibers can be embedded with an
isotropic high thermal conductivity filler material. Suitable filler
materials include CNTs and other high conductivity materials like silver,
diamond, aluminum nitride and boron nitride. Boron nitride and aluminum
nitride have the special property of high thermal conductivity with no
electrical conductivity. The amount of filler embedded varies depending
on the desired application and performance objectives. For example,
filler can be present in amounts of 5% to 50% by volume. By embedding
such fillers, the thermal conductivity of the carbon-based can be
increased to around 2,000 watts per meter-Kelvin along its length. As
used herein CNT includes Single Wall CNT (SWCNT) and Multi Wall CNT
(MWCNT), and combinations thereof. SWCNT and MWCNT have different
conductivity and structural properties, whereas the choice between the
two can depend factors such as the amount of heat to be transferred.

[0042]The carbon-based fibers, whether embedded with filler or not, may
also be coated or clad with a high thermal conductivity material 28.
Suitable coating or cladding materials include aluminum, copper, silver
boron nitride, diamond and CNTs. The thickness of the coating or cladding
may vary depending on the application and performance objectives, and
desired final density of the composite. For example, the coating or
cladding may range in thickness from 100 nm-5 μm. According to on
non-limiting example, the coating thickness is approximately 0.5 μm.

[0043]The anisotropic carbon-based fibers can be spun and aligned to form
linear matrix, and then heated to sinter the clad or coated materials to
fuse the fibers 28 together. The fibers adhere to each other and pull
close together into a compacted or dense matrix. The process boosts the
density of the matrix by 5 to 25 times. Other factors being equal, higher
density results in better thermal conductivity. Several other factors may
also affect the density of the resulting matrix, such as the fiber
diameter, density, type and quality of the embedded high conductivity
filler material, and the CNT type (single wall or multi-wall). When
present, the manner in which the CNTs are grown can also be an important
factor that impacts the resulting shape and density of the matrix.

[0044]The coating or cladding 28 deposited on the anisotropic carbon-based
fibers 20 can be provided with any suitable thickness t. For example, in
order to fill the voids between longitudinal fibers to obtain a
theoretical packing density of the matrix of 89.7%. As shown in FIGS.
3A-3B, the thickness t of the cladding 28 required to fill the void
between compressed fibers 20 is when t=0.0502r. With r being the mean
radius of the fiber and R=r+t. For a packing density of more than 80%
t=0.055r. The range of fiber diameters used can optionally be r=2.0
nm-100 μm, more specifically 10 nm to 50 μm, and even more
specifically 2.5 μm-10 μm. The void fill area A=0.1616r2.

[0045]According to an alternative embodiment, the composite of the present
invention may comprise the abovementioned anisotropic carbon-based fiber,
high thermal conductivity filler and a foam material. Foam composites are
made by air blowing and foaming similar to the way all metal foam
composites are manufactured. The foam composites of the present invention
made from anisotropic carbon-based fiber will be lighter than metal foams
made solely from aluminum.

[0046]According to a further embodiment, the embedded and/or clad
anisotropic carbon-based fibers 20 can be woven in various patterns,
thereby forming a woven matrix composite designer material 31. One such
woven composite structure is shown in FIG. 4. This is a cross-section
illustrating the transverse heat path 32 and thermal gradient 34 through
this particular woven matrix composite 31. For applications requiring
heat spreading instead of linear thermal conductivity, the matrix can be
designed to have very high thermal conductivity in the X and Y direction
compared to its Z direction. By choosing weaves with a given direction
like only X or only Y, the spreading can be controlled or improved only
in that chosen direction. When the matrix is designed to have the thermal
conductivity in X, Y and Z directions to be different from each other,
the heat spreading will all be different from each other, thus making the
heat spreading eccentric. The thermal conductivity in metals like copper
and aluminum, which are often used in such applications, is the same in
all the three directions. By contrast the designer materials of the
present invention allows the thermal spreading properties to be
controlled in chosen directions.

[0047]The composite matrix of the present invention can be provided with
any suitable size or dimension. For example, the composite matrix can
have a thickness from 10 nm-1,000 μm, more specifically 10 nm-800 nm,
or 1 μm-1,000 μm. According to an alternative embodiment, a
plurality of layers of composite matrix material can be fused together to
build a thicker composite matrix. FIG. 5 shows multiple layers 42, 44,
46, 48, 50 of composite matrix material which can form the basic building
blocks for cooling or heat transfer components. Each layer of composite
matrix material can be provided with distinct dimensions, weave pattern
or orientation, and/or composition to impart the desired properties to
the resulting cooling or heat transfer component formed therefrom. For
example, an eccentric thermal conductivity profile can be achieved by
varying the number and type of the composite matrix material layers in
building a cooling or heat transport component therefrom. According to an
illustrative non-limiting example, each of the layers has a thickness T
of 20 μm to 100 μm.

[0048]The composite matrix material and cooling or heat transport
components formed therefrom can be made by any number of suitable
techniques or methods. The following is an illustrative, non-limiting
discussion of such techniques and methods.

[0049]There are many considerations to keep in mind for the manufacture of
the anisotropic carbon-based fiber embedded with high thermal
conductivity fillers of the type mentioned above, like CNT and other
nano/micro materials. It may be advantageous to collocate different
related and associated manufacturing, testing and quality control
processes to minimize the total cost of production by making the whole
manufacturing process continuous. It may also minimize the post
manufacturing and shipping processes generally associated with
distributed manufacturing processes.

[0050]The manufacturing process can be continuous starting from the
mesophase or the liquid crystal phase of the carbon fiber precursor
material, until and including the finished product line of a cooling or
heat transport component. The different steps of the continuous processes
may include one or more of the following, in any particular order.

[0051]One or more high thermal conductivity nano and micro filler
materials, such as CNTs and diamond, are embedded into carbon fiber at
the mesophase and during the drawing of the fiber through fiber-drawing
dies and the fiber spinnerets. The amount filler materials used depend on
the desired increase in thermal conductivity. The drawing orifice chosen
depends on the amount and type of filler materials as well as the
filament diameter that make up the spun carbon fiber. If the orifice is
smaller than a micron, the filler material and the carbon fiber filament
become few hundred to hundreds of nanometers as the fiber filament drops
down due to gravity and joins the other filaments from the other orifices
of the drawing tool, thus resulting in thinner spun fiber. If diamond is
used as the filler, the conductivity in the Z direction is also higher,
because diamond has much higher conductivity than carbon fiber in all the
three directions. The spun fiber has much higher thermal conductivity
than unfilled carbon fiber due to CNT and other embedded nano and micro
materials.

[0052]The next steps may include heating, re-crystallization and cooling
through a continuous microwave heating and cooling process. Depending on
the desired thermal conductivity, heating up to the mesophase formation
temperature is required. This temperature can be on the order of
2000° C. to 3000° C.

[0053]The heat treated fiber can be sent through a pretreatment process
for coating or cladding. A variety of metals with high thermal
conductivity, such as copper, is coated on the fiber. The coating
thickness can be approximately 10 nm-5 μm, and is controlled by the
speed at which the fibers pass through the plating cycle.

[0054]The coated or clad fibers may be sintered together, as described
above, which allows the fibers to come together or densify.

[0055]The fiber can be spooled into an array of spools.

[0056]The fibers may be sent through a fiber line up and weave processes.
FIG. 6 shows a cross-woven matrix 52. This is a reel to reel process. The
process may include two steps: in-line weaving and cross weaving. The
woven fibers can go through a continuous microwave sintering process,
where the coated fibers get fused while at the same time forming a woven
composite designer matrix material.

[0057]The composite matrix material may be layered and fused together by a
continuous roll-to-roll heating process. The type and thickness of the
layers are chosen to define the thermal conductivity of the final
designer matrix.

[0058]The designer composite matrix layers or films can be spooled into a
shippable array of spools for use in the subsequent manufacture of a
variety of cooling or heat transport devices or components.

[0059]Some heat transport components may even be manufactured in
collocated next steps. A full range of cooling or heat transport
components and materials can be made at least in part from a composite
material of the present invention. Components and materials to include
thermal interface materials (TIM), heat sinks, heat pipes, microchannel
heat transport components, heat spreaders, stiffeners, packaging
materials, PC board laminates, substrate material, microprocessor lid and
other specialty packaging materials.

[0061]According to a further embodiment of the present invention, a heat
transport device is provided. A heat transport device of the present
invention can be formed, at least in part, from the composite matrix
designer material described above. An exemplary heat transport device 60
is illustrated in FIG. 7. It bears emphasizing that the present invention
is not limited to the particular device illustrated in FIG. 7. In the
illustrated embodiment, the device 60 comprises an internal passage 62
optionally having one or more ducts 64. The ducts 64 can have any
suitable dimensions, such as a width of 10 nm-5 mm. The ducts 64 can be
designed to have a high aspect ratio, such as at least 10:1 or 50:1, of
height H to width W. At least a portion of the internal passage 62 and/or
at least a portion of the one or more ducts 64 is formed from the
designer composite matrix material. As illustrated in FIG. 8, the ducts
64 can be imprinted with nano grooves 66 and/or spikes 68 to create
turbulence and hence efficient heat transfer from the channel surface.
Instead, or in addition, CNTs 70 can be coated on the one or more of the
inside walls of the ducts 64.

[0062]A heat transfer media 72 may be provided within the internal passage
62 and in communication with the at least one duct 64. The heat transfer
media 72 can contain CNTs and/or other nano or micro size particles 74 to
help create the turbulence and break up laminar flow to enhance the
convective heat transport efficiency. The CNTs and/or nano or micro
particles 74 impinge on the walls of the ducts 64 and collect heat
therefrom then bounce back into the heat transfer media 72 and quickly
disperse and transfer the heat into the heat transfer media 72, thus
acting as heat transfer agents between the ducts 64 and the heat transfer
media 72. The particles 74 also break up laminar boundary layer flow and
create or add to the turbulent flow of the heat transfer media 72. Only
appropriate volumes of these high conductivity particles 74 should be
added to the heat transfer media 72 to minimize any coagulation/lumping
in the fluidics channel system, valves, filters, membranes and pumps
which may be present in such systems. Alternatively, the heat transport
device 60 may comprise a closed system containing a set volume of heat
transfer media 72, that may circulate, if at all, only in a closed loop.
Appropriate curvature is designed into the ducts 64 to enhance the fluid
flow turbulence. The inside walls of the ducts 64 may be provided with
CNTs and/or nano/micro fibers 70 are grown vertically from the surface
protruding into the heat transfer media. These protrusions transfer the
conducted heat into the heat transfer media, swaying back and forth in
the flow thereof.

[0063]The heat transport device 60 can be manufactured by any suitable
technique. For example, nano-imprint lithography (NIL) can be used as a
low cost method for forming nanometer-scale features such as ducts,
nano-grooves and/or spikes. This method also conforms to the
International Technology Roadmap for Semiconductors. NIL may be the
lithography solution at the 32 and 22 nm fabrication nodes.

[0064]According to an additional embodiment of the present invention, a
heat transport device, of the type described above, is incorporated into
an arrangement including one or more solar cells, and is used for cooling
the solar cell and/or transporting heat for other uses. An exemplary
arrangement 80 is illustrated in FIG. 9. As illustrated therein, the
arrangement 80 includes a solar cell 82. The solar cell 82 comprises a
first surface 84 and a second surface 86. The heat transport device 60 is
placed in thermal communication with the solar cell 82, optionally in
thermal communication with at least a portion of the second surface 86.
According to one embodiment, a heat transport device 61 is in
communication with the entire second surface 86 of the solar cell 82. The
heat transport device 61 may be formed at least in part from the designer
composite material as described herein. The heat transport device 61 may
otherwise have any suitable configuration. Thus, for example, the heat
transport device 61 can be an actively cooled device having a heat
transfer media circulated therethrough (e.g. FIG. 10). Alternatively, the
heat transport device 61 can comprise a passive device having a sealed
internal chamber 63. A heat transfer media may be provided within the
chamber 63. According to a further alternative embodiment, the heat
transport device 61 is provided with one or more of the features
described herein in connection with the heat transport device 60. The
arrangement 80 may include a thermal interface 88, material (TIM) between
the solar cell 82 and the heat transport device 60. The thermal interface
material 88 is thermally conductive, electrically conductive, or both.
One suitable thermal interface material is a silver-based material. The
solar cell 82 can be mounted directly on the heat transport device 60
without the use of the package that comes with the solar cell 82. Because
the solar cells 82 are typically mounted on a substrate and packaged with
materials which have a comparatively low thermal conductivity, mounting
the solar cells directly on the cooling assembly enables maximum heat
transfer from the solar cell to the heat transport device.

[0065]Alternatively, the present invention can be combined directly with
conventional packaged solar cell arrangements that include a standard
solar cell soldered onto a 15 mil thick ceramic substrate having
electrical connectors provided thereon, and still provide advantages and
benefits due to the exceptional cooling and heat transport properties.

[0066]According to a further embodiment, the arrangement 80 additionally
may comprise optics or other suitable means 90 for producing concentrated
solar energy 92 incident upon the solar cell 82. An arrangement formed
consistent with the principles of the present invention is capable of
amplifying the concentration of sunlight up to, for example, 10,000 times
the nominal solar intensity level (10,000×). Additional optional
features of the arrangement include electrical connections 94 and a
printed circuit board 96. In addition, as illustrated in FIG. 10, the
heat transport device 60 may additionally include an inlet 98 and outlet
100 for circulation of a heat transfer media therein. Finally, it should
be understood that the arrangement may include an array of solar cells. A
single heat transport device can be associated with the entire array.
Alternatively, each individual cell may be provided with a corresponding
heat transport device, or any variation is also envisioned wherein there
are fewer individual heat transport devices than the number of individual
solar cells (i.e., each heat transport device is associated with a
plurality of individual solar cells that are smaller in number that the
number in the array).

[0067]According to a further embodiment of the present invention, a heat
transport device, of the type described above, is incorporated into the
cooling system of a nuclear power generation operation. The heat transfer
media described above may optionally be utilized with or without the heat
transport device. The improved efficiencies of the heat transport device
constructed according to the present invention and/or the use of the heat
transfer media described herein should provide greater cooling while
requiring lower volumes of coolant than conventional arrangements.

[0068]An arrangement formed according to the principles of the present
invention may include a combination of heat transport devices and other
heat transport and/or cooling system components. FIG. 11 shows an
arrangement 110 wherein heat transfer media flows across the solar cell
strip 112 through manifolds 114. One example of the heat transfer media
is water. Heat transfer media enters the manifolds 114, passes through
the solar cells 112, picks up the heat and carries the extracted heat
away. The main heat transfer media inlet 116 is designed to be maintained
at a level higher than the manifold 114 and the heat transfer media
outlet 118 out of the manifold 114 is designed to be maintained at a
level lower than the manifold 114, so that heated media does not enter
back into the solar cells 112. Flow rate through the manifold 114 is
controlled based on the amount of incident sun light on the concentrator
and the solar cell strip 112.

[0069]FIG. 12 shows an alternative arrangement 120. In this embodiment,
the same general features are present as in the embodiment depicted in
FIG. 11. However, in the embodiment of FIG. 12, heat transfer media inlet
122 and the heat transfer media outlet 124 are constructed such that the
direction of the flow of fluid is not significantly changed by the
arrangement.

[0070]As illustrated, for example, in FIGS. 9, 11 and 12, the heat
transport arrangements of the present invention, as described herein, may
be directly connected to solar cell arrays or strips. In other words,
cooling or heat transport arrangements of the present invention can be
combined with conventional solar cell constructions, but where the
substrate and/or mounting components of such conventional solar cell
arrangements has been removed so as to allow direct connection between
the solar cell arrays or strips with the cooling or heat transport
arrangements of the present invention, thereby improving the cooling/heat
transport performance of the overall arrangement. Alternatively, the
present invention can be combined directly with conventional solar cell
arrangements that include their standard substrate and/or mounting and
still provide advantages and benefits due to the exceptional cooling and
heat transport properties as described herein.

[0071]All numbers expressing quantities of ingredients, constituents,
reaction conditions, and so forth used in the specification are to be
understood as being modified in all instances by the term "about."
Notwithstanding that the numerical ranges and parameters set forth, the
broad scope of the subject matter presented herein are approximations,
the numerical values set forth are indicated as precisely as possible.
Any numerical value, however, may inherently contain certain errors
resulting, for example, from their respective measurement techniques, as
evidenced by standard deviations associated therewith.

[0072]Although the present invention has been described in connection with
preferred embodiments thereof, it will be appreciated by those skilled in
the art that additions, deletions, modifications, and substitutions not
specifically described may be made without departing from the spirit and
scope of the invention. Terminology used herein should not be construed
in accordance with 35 U.S.C. §112, 6 unless the term "means" is
expressly used in association therewith.